Problems involving infant sleep-wake regulation during the first year of life concern 30-50% of families with infants. This project attempts to better understand the possible origins of these problems. The relationship between patterns of early sleep-wake regulation to later sleep disturbances, persistent sleep problems and later behavior problems is unknown, although sleep disturbances persist and many childhood behavior disorders are associated with disturbed sleep. A guiding hypothesis of this program of studies posits that normal development of sleep-wake state consolidation results from complex interactions between the infant's biology and the psychosocial environment. These factors are mediated, in part, through bedtime and night time interaction in the parent-infant relationship. This study examines the effect of a "sleepaid" intervention on the regulation of infant sleep-wake states and on maternal well being. Eighty full term, normal infants and their families, who meet selection criteria, are recruited and randomly assigned to 1 of 2 groups: representational sleepaid (RSA) or sham control (SC). All families are assessed at preintervention, when the infant is 2 weeks old, and at five ages from 1 to 12 months of age during the intervention period. Mothers in the RSA group are given a T-shirt (representational sleepaid) which they wear as a nightgown for 14 nights during sleep. Their infant is exposed to the T-shirt during mother-infant interactions each night from 2-4 weeks of age. During exposure, the T-shirt incorporates olfactory attributes of the mother. Infant exposure occurs during mother-infant interaction around night time feeding and comfort (vestibular stimulation). At 4 weeks of age, the T-shirt is placed in the infant's crib (as a sleepaid), and the infant's sleep-wake consolidation, maternal bedtime-night time interaction and maternal well being are measured at regular intervals. Mothers in the SC group are given the same T-shirt but never wear it. The SC sleepaid is also placed in their infant's crib at 4 weeks of age. Sleepaids are refreshed (rewearing for RSA group, rewashing for SC group) at monthly intervals during the intervention trial. Intervention assessments of infant sleep-wake consolidation and bedtime-night time interaction are obtained longitudinally at 1 mo., 3 mo., 6 mo., 9 mo. and 12 mo. of age. Two consecutive nights of all- night timelapse videosomnography are recorded. Measures of maternal well being, infant temperament, infant development and environmental stresses are also obtained at regular intervals. It is posited that infants who have had exposure to the RSA will have, at 1 year-of age, compared to infants without exposure (SC), more mature sleep-wake state consolidation, less signaling awakenings during the night and be users of sleepaids. Mothers will have an improved sense of maternal well being.